HIV-1 DNA ultra-deep sequencing analysis at initiation of the dual therapy dolutegravir + lamivudine in the maintenance DOLULAM pilot study.

Background: The DOLULAM study assessed the efficacy of dolutegravir + lamivudine dual therapy to maintain virological suppression in heavily treatment-experienced HIV-1-infected adults. No virological failure occurred during the first year of the dual therapy.
Objectives: A virological substudy was conducted to assess the prevalence of M184I/V mutations at dual therapy initiation using historical DNA/RNA genotypes and baseline DNA genotype obtained by next-generation sequencing (NGS).
Methods: HIV-1 RT sequences were obtained from DNA and/or historical RNA using Sanger technology. HIV-1 DNA RT and integrase NGS was performed using Illumina® technology.
Results: Among the 27 patients enrolled in the DOLULAM study, historical HIV DNA and RNA Sanger sequences were available in 14 and 18 patients, respectively. At the initiation of DOLULAM, DNA NGS genotypes showed that 45% and 21% of the patients harboured minority resistant variants (MRV) in RT and integrase, respectively. Combining all available genotype data, an M184I/V was observed in 17 of 27 (63%) of the patients. Most M184V were detected in historical RNA genotypes (n = 8 of 11), whereas M184I were exclusively detected in DNA genotypes (n = 10, including 7 as MRV). Ten patients displayed defective viral genomes in cellular reservoirs, all including M184I and stop codons. At the time of DOLULAM initiation, M184V was observed in DNA NGS in five patients, including one as MRV. Conclusions: These first NGS data on HIV DNA at initiation of a switch study showed (i) a high proportion of patients harbouring defective viral genomes, whose mutation M184I is a marker, and (ii) a low number of patients in whom M184V remained as a major viral variant in PBMCs.